Aerial closures are generally employed to enclose joined or spliced suspended cable for protecting the splice or termination from the elements.
The telecommunications cables are suspended between poles, towers, or the like. Typically, twenty-five or more pairs of insulated wires for conducting electrical signals or optical fibers for conducting light signals are enclosed in a braided sheathing which in turn is enclosed in an insulated cable sheath. In some telecommunications cable, the cable does not have sufficient inherent strength to support its own weight between the poles, therefore, a support strand is suspended between the poles above and in parallel with the cable. Periodically along the length of the cable it is tied or clamped to the support strand. In other installations, the support strand is enclosed in the sheathing around the telecommunication cable to form a self-supporting cable.
A splice in the telecommunication cable is generally required for connecting ends of cable segments. For example, a splice is required where the distance between the two places to be connected is greater than the length of a roll of telecommunications cable. A splice is also required to form a branch or drop line that extends from the main cable to service a particular subdivision, facility, or individual customer.
Terminal blocks are generally employed for connecting corresponding pairs of conductors to form a splice in the aerial terminal system. An enclosure of the type disclosed in U.S. Pat. No. 4,721,830 is often employed for enclosing cable splices for protection from the environment, plants, and animals.
The typical aerial cable enclosure includes a housing formed of two housing members joined by a hinge and a header member connected to the support strand. The aerial closure disclosed in U.S. Pat. No. 4,721,830 is constructed such that one of the housing members is suspended from the header member by a pair of straps and the other housing member is suspended from the first housing member by a hinge. When the housing members are in the open position and disengaged from the header member, the housing members are suspended below the cable segments, thereby providing access to the ends of a cable segments.
Aerial terminal systems incorporating cable enclosures of the type disclosed in U.S. Pat. No. 4,721,830 are typically installed a predetermined distance, for example, 18 inches, from the center of a pole in a series of poles supporting the telecommunications cable. An opening is formed in the cable sheath and a strand clamp is attached to a support strand or messenger cable that conventionally supports the weight of the telecommunication cable.
Aerial cable enclosures of the type disclosed in U.S. Pat. No. 4,721,830 are commercially available from Communications Technology Corporation of Dallas, Tex. under its registered trademark "HAWK" and with terminal blocks mounted in the enclosure under the trademark "TERMAX".
Cable closures of the type disclosed in U.S. Pat. No. 4,810,829 and commercially available from Minnesota Mining and Manufacturing Company under the trademark "SLICK" comprise a generally cylindrical casing formed as a single unit with a compression molded longitudinally extending hinge on a single deformable unit to provide a pair of semi-cylindrical casing sections, one of which is connectable by hangers to a support cable. One of the semi-cylindrical casing sections is pivotally movable relative to the other semi-cylindrical casing section to provide access to the cable splice.
End seals for aerial closures are disclosed in U.S. Pat. No. 4,701,574 and U.S. Pat. No. 4,857,672 to provide environmental protection between the ends of the closure and cable segments.